Inadequate pilot training by Air France and mistakes by a young co-pilot contributed to a mid-Atlantic Airbus disaster in June 2009, an official report indicated yesterday.

The cockpit crew on the Rio-Paris flight responded incorrectly to defective speed recorders and failed to notice that the Airbus A330 had stalled, despite repeated warning signals, the report said. Flight recorders recovered from the ocean bed earlier this year showed that the crew failed to make any announcement to passengers as the airliner dived towards the south Atlantic for more than three minutes.

The French air accident investigation bureau issued 10 urgent recommendations yesterday, including mandatory training of pilots in manual flying at high altitude. The investigation bureau said neither of the co-pilots on flight AF447 had received recent training in manual flying at high altitudes or in responding to faulty speed readings.

Air France immediately issued a counter-statement defending the professionalism and courage of its crew. Air France appeared to try to shift the blame to Airbus by suggesting that "repeated and misleading" stall alarms sounding in the cockpit had "enormously contributed to the difficulties of the crew in analysing the situation". Both Air France and Airbus have been placed under formal investigation for manslaughter by the French judicial authorities.

Yesterday's report implicitly blamed Air France. It confirmed that, in the absence of reliable speed recordings, the automatic pilot returned the aircraft to manual control. The captain had left the flight deck, and the 32-year-old second co-pilot who took over the controls lifted the nose of the plane, which is the opposite of what he should have done.